Building codes for multi-story buildings require that piping or conduits through concrete floors be arranged in such a manner as to avoid fire and smoke migrating between floors through conduit passages. Various methods have been used to meet the code requirements. For example, one method is to pass a conduit through an oversized opening in the concrete floor and then to pack some form of fireproof compound about the conduit in the opening. Methods of this type have been approved by Underwriters Laboratories using materials such as 3M Fire Barrier CP 25 caulk from 3M Corporation or FS sealant from Dow Corning Corporation. The conduits are typically cast iron or steel pipe so that only the space surrounding the pipe need be insulated.
Another form of fireproof passage utilizes a plastic connector (PVC or similar material) which is attached to a form on which a floor is to be poured. FIG. 1 illustrates this type of prior art device which comprises a pipe segment 10 having a mounting flange 12. The flange 12 is nailed to the form 14 which supports the concrete during pouring of the floor 16. The segment 10 is then stuffed with newsprint or similar material to prevent concrete from entering during pouring. After the concrete has set, the form is removed along with the newsprint and coupling adapters 17 are adhesively bonded to each end of segment 10. The adapters 17 are flexible so that clamps 18 can be placed around their larger end for clamping the adapters in sealing engagement about the cast iron pipe 20.
There are several known disadvantages of the plastic connector, including excessive cost. Further, the adapters 17 are flexible and must set in position several hours to allow the adhesive to bond them to the connector. Still further, the plastic connectors are relatively fragile and have been known to tip over during concrete pouring either from the weight of the concrete or from an accidental collision with a worker or equipment. Accordingly, it is desirable to provide an improved connector which overcomes the above and other disadvantages of the prior art.